Deep Digital Flexor Tendon Injury at the Level of the Proximal Phalanx in Frontlimbs With Tendon Sheath Distension Characterized by Standing Low-Field Magnetic Resonance Imaging in Horses: 13 Cases (2015-2021).
Authors: van Veggel Elisabeth Cornelia Susanna, Selberg Kurt T, van der Velde-Hoogelander Brenda, Vanderperren Katrien, Cokelaere Stefan Marc, Bergman Hendrik-Jan
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Traumatic injury to the deep digital flexor tendon (DDFT) at the proximal phalanx—specifically at the anatomical transition where the tendon changes from an ovoid to a bilobed cross-section—represents a distinct and clinically challenging lesion that can be reliably identified using standing low-field MRI. Over a six-year retrospective review, researchers identified 13 horses presenting with DDFT injury at this specific location accompanied by flexor tendon sheath distension, demonstrating that this lesion accounted for 65% of MRI-diagnosed DDFT pathology in horses examined for digital flexor sheath disease. Disappointingly, functional prognosis proved considerably guarded, with only 23% of affected horses returning to their previous level of work and just one horse remaining in active rehabilitation—substantially worse outcomes than those typically reported for other causes of tendon sheath distension. The proximal phalanx junction appears to represent a biomechanical stress point where the tendon's structural change predisposes it to injury, and standing MRI proved instrumental in characterising these lesions where clinical signs alone could mask the true nature of pathology. For practitioners encountering frontlimb digital flexor sheath distension, this finding underscores the value of advanced imaging to identify this specific injury pattern, allowing realistic prognostic discussions and potentially directing management towards conservative long-term care or performance adjustment rather than aggressive rehabilitation protocols based on more optimistic historical data.
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Practical Takeaways
- •DDFT injuries at the proximal phalanx have poor return-to-work rates (23%); realistic expectations should be set with owners when this lesion is diagnosed
- •Standing low-field MRI is a practical in-clinic imaging tool for definitively diagnosing digital flexor tendon sheath distension and identifying DDFT lesions at this specific anatomical location
- •When DDFT sheath distension is present, carefully evaluate the proximal phalanx region where the tendon transitions from ovoid to bilobed, as injuries here carry a guarded prognosis
Key Findings
- •Standing low-field MRI successfully identified DDFT injury at the junction between ovoid and bilobed portions in 65% (13/20) of horses examined for digital flexor tendon sheath distension
- •Only 23% (3/13) of horses with DDFT injury at the proximal phalanx returned to previous level of work, indicating poor prognosis
- •This specific lesion location at the proximal phalanx has a less favorable prognosis compared to other causes of tendon sheath distension
- •Standing low-field MRI is a useful diagnostic tool for evaluating DDFT pathology at the proximal phalanx where tendon morphology changes from ovoid to bilobed